NEW YORK -- It was a rare thing that happened in the Yankees' clubhouse on Wednesday. Manager Joe Girardi sat down where his interrogators usually fire their questions, while three kids joined him. Then Quinn Ostergren, Ryan Tucker and Sean Callahan all signed a one-day contract with the Yankees, joining the ranks of legends from Babe Ruth to Derek Jeter.

But their road to the big leagues has been much different.

Quinn, 4, Ryan, 12, and Sean, 11, are all currently fighting through pediatric brain cancer, and they each are in various stages of chemotherapy recovery. Together with the organization "Friends of Jaclyn," the Yankees were able to give them professional treatment and a caring distraction from their difficult realities.

The celebratory event was a part of the Yankees' sixth annual HOPE Week (Helping Others Persevere and Excel) to help recognize individuals or groups of people that have spectacular stories.

"It's an exciting day here for the New York Yankees," said general manager Brian Cashman, introducing the newest Yankees to the team. "Our job in the front office, with our scouts and our analysts, [is to] always to try and find personnel out there that's going to improve the Yankee tradition, history, and family. We feel that the creative individuals we have up here with Quinn, Ryan, and Sean, that you embody everything that the Yankees aspire to be."

Acting as a temporary Players Association representative, closer David Robertson quickly verified their contracts and let each of them sign their names. Soon enough, donned in pinstripes, they received the Yankee experience, fielding questions from the media under bright flashes and rolling cameras.

"I'm having a lot of fun," said Ryan.

"Yeah," said Sean shyly. "I'm having fun."

The kids began the day with their families at the Hard Rock Café, where they were surprised by various players for lunch. Then they came to the ballpark, unaware of the new jobs and welcoming that awaited them.

"I had no idea the full magnitude of what it is," said Alyssa Ostergren, mother of Quinn, whose first surgery was in 2012 and has four months left of chemo-radiation. "I was thinking we're just going to go to the game, and that's great, and I would've been totally happy with that."

"Friends of Jaclyn" started after Jaclyn Murphy was diagnosed with a malignant brain tumor and given a 30-percent chance of survival. When the Northwestern University women's lacrosse team learned about what Jaclyn was going through and about her passion for lacrosse, the Wildcats "adopted" her as an honorary member of the team. Later that spring, Northwestern won its first national championship.

That inspired Jaclyn's dad, Dennis Murphy, who knew the impact that the team had in helping his daughter's health. He quickly created the foundation to improve the quality of life of pediatric brain tumor patients by pairing them with collegiate and high school sports teams. As of now, Quinn is currently paired with the University of Connecticut women's soccer team, Ryan is coupled with the Fairfield men's lacrosse team, and Sean, made official Wednesday, was adopted by the Army football team, the 500th adoption of the foundation.

"It's been a very emotional day," said Murphy. "Quality of life prolongs life, and you can see the smile in these kids' faces. They're at Yankee Stadium wearing pinstripes, and the last thing on their mind is this insidious disease. So as a parent, for us to experience that, whether it's for a couple of hours, or the day, it's priceless."

Ryan, a diehard Yankees fan, is a cousin of Quinn, and began his battle with cancer when he was only 3 years old. But Wednesday might have been even more overwhelming for Sean, who exited five weeks of isolation and stem cell transplants for the first time Wednesday.

"It's beyond words what this is," said his mother, Jeanine Callahan. "Through Sean's treatment, I've always felt there are certain things you do to heal somebody's body, and that's very important for kids who are battling cancer. But more importantly, you have to do things that heal their spirit and heal their soul, and if you take out that, the body will follow."

Sean was diagnosed when he was just 2, and cancer that started in his lungs metastasized to his brain twice, sending him through radiation and transplants until he was 4. After seven years of remission, the brain tumor returned and he's had three surgeries since last June. Wednesday was overwhelming for him.

"It's a lot for him to take in right now," said Robertson. "He comes out and all of this has been poured on him, but he's handled it very well and seems to be having a good time."

"This is a welcome into the world that says we love you and we support you and we think you're amazing," said Jeanine Callahan. "That's what these kids need."

Robertson shepherded the three guests of honor to right field before the game to stretch with the team after they had each changed into full uniform at their name-plated lockers, next to Jeter and Carlos Beltran.

"We love this week," said Girardi. "You get to give back as a team, and recognize people who are doing amazing things. I've always said that without hope, there's nothing. I think if we can take some time and give back to people who are hurting or going through difficult circumstances, take their mind off that and give them something to look forward to, I think it's extremely important."

It was especially thrilling for Jaclyn, now a 19-year old student at Marist University, cancer free for nine years.

"I've met some really great college players, but to meet actual pro athletes…" she paused, miming her shell-shocked nature. "It's fun to see that these athletes do care and take the time out to help charities. For the Yankees to do this for a whole week is mind-boggling."

Jake Kring-Schreifels is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.